[PATCH 4/4] tmem: fix Out-of-bounds read reported by Coverity

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

From: Bob Liu <bob.liu@oracle.com>

CID 1198729, CID 1198730 and CID 1198734 complain about
"Out-of-bounds read".

This patch fixes them by casting the 'firstbyte' to (uint8_t).

Signed-off-by: Bob Liu <bob.liu@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
 xen/common/tmem.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/xen/common/tmem.c b/xen/common/tmem.c
index f2dc26e..506c6be 100644
--- a/xen/common/tmem.c
+++ b/xen/common/tmem.c
@@ -399,7 +399,7 @@ static void pcd_disassociate(struct tmem_page_descriptor *pgp, struct tmem_pool
 {
     struct tmem_page_content_descriptor *pcd = pgp->pcd;
     struct page_info *pfp = pgp->pcd->pfp;
-    uint16_t firstbyte = pgp->firstbyte;
+    uint8_t firstbyte = pgp->firstbyte;
     char *pcd_tze = pgp->pcd->tze;
     pagesize_t pcd_size = pcd->size;
     pagesize_t pgp_size = pgp->size;
@@ -1231,7 +1231,7 @@ static bool_t tmem_try_to_evict_pgp(struct tmem_page_descriptor *pgp, bool_t *ho
     struct tmem_object_root *obj = pgp->us.obj;
     struct tmem_pool *pool = obj->pool;
     struct client *client = pool->client;
-    uint16_t firstbyte = pgp->firstbyte;
+    uint8_t firstbyte = pgp->firstbyte;
 
     if ( pool->is_dying )
         return 0;
-- 
1.8.5.3